Chain Breaking Pliers

A workshop that breaks chains every day eventually buys a chain plier. The screw-type tool is the universal answer, but if the job is just to open a chain (cleaning, replacement, fitment check) and you're going to do it 20 times this week, the spindle stroke per chain adds up. The Chain Rivet Pliers 1640/1DP collapse that work into a single squeeze. Pin out, chain open, next bike.

This is a drop-forged hand tool, not a sheet-metal stamping. The body is entirely hardened and tempered for fatigue resistance, the driving pin is induction-hardened separately so it doesn't deform under repeated use, and the trivalent chrome plating handles the bench environment that eats unfinished steel. It's built to be the chain plier that sees decades of work, not a season.

How it works

A conventional screw-type chain tool tightens a spindle through perhaps 10 to 15 turns of the handle per chain break. The 1640/1DP replaces that with a single-stroke plier action. The driving pin sits opposite the chain plate, the chain plate sits in the support; close the handles and the pin advances through the chain pin in one continuous motion. The ergonomic design keeps the work in one hand, which matters when the other hand is holding a chain that's still partly attached to a bike on a stand.

Compatibility

The 1640/1DP works on most derailleur chains in current production, but it does not fit 1/8″ (3.3 mm) roller-width chains. That excludes most BMX and singlespeed chains, which use the wider roller width. If your work is mostly singlespeed or BMX, the Master Chain Tool 1647/2BBI is the right pick; its 1/8″ singlespeed support handles those chains directly.

For shop benches that service mixed-fleet bikes, the 1640/1DP is the chain-opening tool you reach for first, and the screw-type stays on the bench for the few chains it won't fit.

Specs

• Most derailleur chains in current production; not compatible with 1/8″ (3.3 mm) roller-width chains (BMX, most singlespeed)
• 240 × 29 × 13 mm
• 426 g
• Drop forged, entirely hardened and tempered
• Pin induction hardened
• Material: premium flex plus carbon steel
• Surface finish: trivalent chrome plated to ISO 1456:2009
• Double-plastic-dipped handles
• Article number: 1640/1DP-US

Built in Zreče, Slovenia

Unior has been forging hand tools in Zreče since 1919, and is the official technical partner of multiple World Tour and downhill teams. The 1640/1DP is one of the tools where the forge heritage shows up most plainly; drop forging is the manufacturing step that makes the difference between a chain plier that survives a shop floor and one that flexes under load. It's not a tool every home mechanic needs, but for a bench that breaks chains daily, it's the cleaner answer.

Pro tip from our mechanics

The plier action is faster than the spindle. The reinstall is the same either way. If you're using the 1640/1DP to break a chain for cleaning, the chain comes off the bike, into the ultrasonic, and back on; if you're breaking it for replacement, the chain plier doesn't reinstall and you'll want the Master Link Pliers 1720/4DP or a screw-type chain tool for the second half of the job. Our chain-replacement guide covers the master-link versus pin-pressed reinstall and which one applies to your chain: When and how to replace your chain →